3DV Seismicity Viewer

About

3D viewers as web page plugins are often difficult to use. Many require
Flash or Java in the browser, which is problematic in several ways. Some
failed to gain traction with the general public due to
complex user interfaces or learning curves.

We wanted a simpler solution, a way to
rotate and zoom in on sets of earthquakes which would be both easy to use
and lack the complexity and security issues of the plugin approach.
3DV uses standard HTML5 techniques to accomplish that goal.

It is normally invoked from the IRIS Earthquake Browser (IEB),
as one of various commands that can be performed on a selected
set of earthquakes. 3DV can also be invoked directly by simply bookmarking it.

This project began in 2011 as a copy of the cool, molecule-viewing
webapp called CanvasMol, with the
gracious permission of the author. Also, Gary Parvis kindly contributed the use of
a regional coordinate conversion algorithm and related source code.

Usage

Use the mouse wheel to zoom in and out.

Drag with the mouse to rotate.

The View menu lets you do things like:

hide/show axes, coastline and/or plate boundaries

reset to a known position, such as "look down" or "look north"

auto-rotate around one or more of the three axes

make the spheres smaller or larger, shaded or solid

enable touch mode, for use on a mobile device

take a snapshot of the scene as a PNG image

Mobile use

On mobile devices the performance will be quite a bit slower. Tablets generally work OK, but the smartphones tested were not very satisfying. Fewer earthquakes, under maybe 800, is best for mobile use.

In all cases turn View / Shading off to drastically improve performance.

Browsers

Internet Explorer before version 9 is not being targeted for support.
V9 is marginally successful, and 10 is a bit better. But WebKit-based browsers, such as Chrome, Safari and (the new) Opera Next, as well as the Gecko-based, such as Firefox, are so much better, and we recommend them.

Opera (before Next) does not get along with 3DV.

Tips

Start with smaller numbers of earthquakes, such as 800, and work up. Turn shading off if things are slow.

The number of earthquakes you view is critical to the performance of rotation and zooming.
If your browser becomes unresponsive (you might even need to restart it), reduce the number
of earthquakes selected in IEB and try again. Older computers and browsers are more
prone to this limitation.

If you drag the with mouse and do not see immediate rotation,
then release the mouse and wait a bit, then consider dismissing that window and starting
again with fewer earthquakes.

Turning shading off in the View menu can
help tremendously.

Finally, the number of other web pages open and programs running
(available memory) is going to affect your mileage.

Savvy computer users will notice that a 3DV URL contains parameters (such as lats; lons; ranges of time, depth, magnitude, etc) which can be changed by directly editing them.
Feel free to experiment, but this method of invoking 3DV is not well-tested at this time.

Although you are able to select very large regions in IEB for viewing in 3DV,
it isn't satisfying. The spherical nature of such regions, the distortion of the axes,
and the erosion of the concept of "up" and "down" make it interesting, but unrewarding. A
rule of thumb would be don't bother with regions that are more than about 1/4
of the world. And more earthquakes, in small-to-medium regions, tends to be more interesting.

Movies

Over time we will build a gallery of various movies either made by ourselves
or submitted by users. Here are a few starters: